Nitrate in water generally originates from sources such as waste discharge, slurry and artificial fertiliser. Nitrite is a product in the oxidation of ammonia to nitrate.

Taking a water sample
Clean tap thoroughly, including the inlet with a flame or disinfectant wipe.
Turn on the tap and allow water to run for a minimum of 2 minutes.
Take the cap off the sterile bottle and immediately fill the container.
Replace the bottle cap as soon as the bottle is full (leaving a small headspace) and record the site and date of sampling.
Deliver to the IEC as soon as possible.
Maintain the water samples at 1-5°C if storing overnight.